Stroke is a major cause of death and disability in the United States and is
a growing public health concern. The latest projections estimate that more
than 1 million strokes will occur annually by the year 2010. Moreover,
stroke has a disproportionate impact on different races. Many studies have
provided strong evidence for lipids as a risk factor for coronary artery
disease (CAD). These studies demonstrate a direct relationship between
total cholesterol, low-density lipoprotein cholesterol (LDL-C), and CAD.
These relationships have not been as clearly established for ischemic
stroke with some studies even questioning whether cholesterol is a risk
factor for stroke.
A population-based study was conducted. Community subjects were
identified by random-digit dialing using dual frame sampling to identify
both published and unpublished telephone numbers. When a household
was contacted, the research objectives were explained and a resident aged
39 years or older was interviewed briefly to record age, six race or ethnicity,
and stroke incidences. These telephone interviews were performed by
trained bilingual interviewers. Totally 533 people were interviewed. The
race breakdown was 283 Hispanic, 150 Black, and 100 White. A total of
160 people experienced strokes before, of which 45% was Hispanic, 37%
Black, and the remaining White. Can the statement “stroke has a
disproportionate impact on different races” be supported by the data?
2a) Explain what kind of statistical problem (for instance, a confidence
interval problem) is it? (5%)
2b) Write down any formula(e) you use. (5%)
2c) Give your opinion on whether you support the statement. Show
detailed calculations (please carry 2 decimal places in your calculations). (19%)
台科公司在5 個月內生產了25 批的智慧型機器人,總經理得到下列的數據:
a. 請製作迴歸線。(10%)
b. 請計算出R2 。(5%)
c. 該總經理認為R2 數值大於0.7,可以做出下列的推論:
c1. 本數值計算出的迴歸線具有良好的配適度。
c2. 由迴歸線可以做出有用的預測。
請評述以上兩點的正確性,並請說明理由。(10%)
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